Telephone system



Nov. 9 1926.

E. L. BAULCH TELEPHONE SYSTEM Filed Oct. 9. 1924 2 Sheets-Sheet ll/nvenor [mes L. lBau/0") Q by my,

im. .9, 192s,l 1,606,139

- Y. l E. l.. BAULCH TELEPHONE SYSTEM Filed Oct. 9. 1924 A 2`Sheets-Sheet 2 Patented Nov. 9, 1926.

, UNETE STATES PATE? ,GFFECE ERNEST L. BAULCH, QF MILLBURN, JERSEY,ASSIGNOR TO WESTERN ELECTRIC l COMPANY, INCORPORATED, 0F NEW YORK, Y.,ACORPORA'IIONOF NEW YORK.

TELEPHONE SYSTEML Application led October 9, 1924. Serial No. 742,504.

nection desired. Calls intended for throughv connections are transferredto the through position and delayed inward calls are transferred to theoutward position.

As to outgoing calls, it is customary for the operator at an A operatorsposition at which such calls may originate, to make use of the serviceof a recording operator who is reached over a recording trunk and waoprepares a ticket bearing the number of the calling party and the numberof the wanted party who may be reached over a long distance connection.The recording operator transmits the ticket to an 'outward toll operatorwho then selects a toll line leading in the proper direction, 'and whenthe operator at the distant end extends the call to the wantedsubscriber, this outward operator in turn extends the connection to thecalling subscriber through a B operators lposition as is well known inthe art.

It is an object of this invention to simplify the extension of outgoingcalls over toll lines in systems of the above type for certain kinds oftraffic, for example, where the calling subscribers are located in the-ysame exchange and the wanted subscribers may be reached overcomparatively short lines1 that is, in cases where a large proportion ofthe calls from the originating ex-v change are for subscribers in nearbytowns or suburbs. It has been found that it is not always practical, inparticular for small exchanges, to have their recording operators attendto such short haul traflic. This is due principally to the fact that thecost of such service often exceeds the collectible revenue.

Another object is the provision of a simpliied traliic system of thistype that is so designed as to give the maximum flexibility and meansforcontinued growth with the least possible equipment of the more costlykind such as recording operators position and ticket distributingequipments.

To attain thesev objects in accordance with onefeature of the invention,there is provided at certain A operators positions multiple jackextensions for short toll lines by means of .which the A operators mayextend connections over such toll lines directly ,from local subscriberswithout the assistance of either a recording operator, an outwardoperator or a B operator. In some instances it may bel advisable to havethese multiplejacks at the A operators positions marked or otherwiseidentified by the name of the towns or suburbs to which the associatedtoll lines extend or else provide the A operators with writteninstructions ts to the terminating points of such toll mes.

Another feature of theinvention relates to the provision of meanswhereby a. connection established by an operator over a toll line cannotbe interfered with by another op erator even though such otheroperatormay disregard the usual busy signal provided for this purpose andattempt to establish a connection by inserting her plug into the jack ofthe engaged toll line.

Another feature relates to the provision of means for facilitating thetransmission of supervisory signals between the operator at a distantend of the toll line and A operators'connected at the multiple jacks ofsuch toll line. t

Another feature relates to the arrangement of these multiple jacks inthe circuits of the toll lines in `such a manner that the ordinaryincoming, through or outward toll operators jacks are normally connecteddirectly to the toll lines while the multiple jacks are connected onlyon the insertion of the A operators plugs in such jacks. Thisarrangement is of advantage in that the circuits for the regular tollline service are normally maintained intact with Vthe least possibleintermediate or encumbering switching devices involved.

'The invention may be more fully understood by referring to theaccompanying drawings, in which Fig. l represents a pre ferred form oftoll line provided with regular t^ line jacks and a multiple jack llUequipped in accordance with this invention. Fig. 2 represents a modifiedforni of toll line provided with equipment for performing supervisoryfunctions between the operator at the distant end and the localoperator.v Fig. 3 shows, in schematic form, a typical layout of theordinary. toll line traffic system and the applicants invention asapplied to such a system.

Referring now especially to Fig. 3?, the arrangement of the' inventionas applied to an ordinary tolll traffic system will be described. ln'lthe case of incoming calls, the inward toll operator at position lmayreceive the call by inserting plug 2 in pick 3 of toll line 4 and afterascertaining the number of the wanted subscribers line, she inserts plug5 into jack 6 of a switching trunk 7 leading to aB operators position22A and transmits the information to this operator who answers the callby inserting plug 8 intov jack 9l of the switching trunk 7. The Boperator now proceeds to extend the connection to the wanted subscriberby inserting'her plug 10 into `iack 11 and complete the call to thewanted subscriber 12 in the usual manner. Y If the incoming call isintended for a subscriber located 4at a distant exchange, the inwardoperator transfers the call to the through operatorat position 13 andthis operator by inserting plug 14e into jack, 15 and plug 16 into jack17 extends the c'all to the outward trunk 18 leading to a distantexchange; or, if as is the case indelayed or similar types of calls, theinward operator decides to have the outward operator at position 2Oyattend to the incoming call, the connection is transferred to liack 19and this operator will thus be notified that her assistanceis required.`

On the other hand, if an outward connection is desired, the outwardoperator at position 20, the recording operator at position 21 and the Boperator at 22 are ordinarily involved in the following manner. In thiscase, a lo-cal subscriber, such as the one located at 25, will connectwith an A operator at position 26, who after having` answered the callby inserting plug 27 in jack 28, ascertains the number of 'the wantedsubscriber at a distant exchange and proceeds to insert plug 29 intojack 30 of a switching trunk 31 leading to a recording operatorsposition 21. This operator answers by inserting plug 33 in jack 34 andnow receives not only the wanted subscribers number but also the callingsubscribers number from thev A operator, prepares a vticket containing`these numbers and transmits the vsaine through a ticket distributingsystem,

well known in the art to the outward operato'r at position 20. Thisoutward operator then Vproceeds to secure a connection to the distantexchange over a toll line such as 4 kof h andling by the use of an orderwire well known in the art. Villien the toll line has been assigned, sheinserts plug 35 into jack 19 and completes, by the aid of the operatorat the distant exchange, a connection to the wanted subscriber. When thewanted subscriber has been reached, the outward operator inserts plug 37in jack 38 `of switching trunk 39 leading to the B operator at position22 who in turn extends the connection to the calling subscriber 25 andthus the connection with the subscriber at 25 and the wanted subscriberthe distant exchange is completed independent of the A operator atposition 26' and the recording operator at position 21, which operatorsare therefore not further concerned with this connection.

lt should be noted that this procedure of completing toll connection israther elaborate and time consuming and when the wanted subscriber maybe reached through toll lines leading to nearby towns, the revenuecollectible for such connections is comparatively7 small and in vmanyinstances is not commensurate with the cost of the service rendered inextending the connections. rllherefore, in accordance with thisinvention, a number of short toll linesv such as el, lea dingv tosurrounding towns to which the traffic is particularly heavy may beequipped with appropriate, circuits and multiple jacks at A operatorspositions. By such an arrangement, local subscribers desiringconnections to nearby towns may secure such service without having towait or to be recalled when a toll connection has been established andthe cost of such toll service will therefore be considerably reduced.`lt would, of course, not be practical to provide such service in allexchanges but rather in exchanges in such cities or towns where theregular long distance traffic is all that can ordinarily be handled bythe existing recording operators equipment and whe/re such traffic mayten'iporarily increase as, for example, would beY the case in citieslocated near seaside resorts or summer colonies to which the tollservice would be particularly heavy during the openseasons. In suolicities the toll lines leading to these surrounding towns or colonieswould be equipped with jacks at A operators switchboards and preferablymarked with ythe name of such places or otherwise identified by theoperator so that when outward calls are received for suoli towns orcolonies from a local subscriber such as 25, the A operator at' 26 may,instead of passing` the call to the recording operator at position 2l,select a jack associated directly with a toll line leading to such town,for example` jack 40, and thus expedite the service and reduce the costshort haul traiiic.

Referring now particularly to Fig. l

which shows an embodiment of the invention as applied to toll line 4, itshould be noted that a complete disclosure of the cir cuits associatedwith this toll line is shown, that is, for the extension of calls toythe inward operator through jack 3 for throughv service through jack15, outward service through jack 19 and outward service from the Aoperators position through jack 40. A detailed description of thefunctions taking place in this circuit during thev extension of thesevarious types of calls will now be made beginning with the reception ofa call through the incoming jack 3. In this case, the incoming call overtoll line 4f causes the operation of the alternatingv current responsiverelay 50 which closesa circuit for relay 52 as follows: battery, makebefore-break contact of relay 53, winding of relay 52, armature andfront contact of A relay 50 to ground. The operation of relay 52 closesan obvious circuit for relay 54 at its armature and front contact Aandrelay 54, in operating, closes a locking circuit for itself through itsleft-hand armature and front contact to battery at the make-before-breakcontact of relay 53. The operation of relay 54 also closes a circuit forbusy signals 57 and 58 located respectively at the through and outwardoperators positions. This circuit may be traced from battery, right-handarmature and front contact of relay 54, winding of busy signals 57 and58 in series toy ground. The operation of relay 54 also closes a circuitfor relay as follows: battery, right-hand armature and front contact ofrelay 54, inner upper armature and back contact of relay 56, winding ofrelay 55 to ground. The operation of relay 55, closes'at its upper outerarmature and front contact an obvious circuit fo-r busy signal 70associated with multiple jack 40, and closes also at its lower armatureand front contact a circuit from battery for the sleeve lead of themultiplejack 40 so as to provide a busy test potential Von this 1 jackfor the A operator i-n case she should disregard the busy signal 70 andattempt to establish a connection to this engaged toll line by insertingher plug 29 in jack 40. It should also be noted that relay 55, inoperating, closes at its inner upper armature and front contact a seriescontact for an all busy signal circuit such as is commonly used incircuits of this type. The lamp 59 at the inward operators position 1 isalso illuminated the moment relay 54 operated over a circuit as follows:battery, make-beforebreak contacts of relay 53, left-handV armature andfront contact of relay 54, righthand armature and back contact of relay60, right-handV armature and back contact of relay 6l, signal 59 toground. The inward operator is thus notified that her attention isrequired for an incoming call on this toll line.

In answering this call, the inward opera-` tor as hereinbefore stated,inserts plug 2 in jack 3, thus completing a circuit for relay l53 asfollows: battery, sleeve contacts of plug 2 and jack 3, left-handarmature and back contact of relav 61, left hand armature and backlcontactuof relay 60, wind.

ing of relay 53 to ground. The operation of relay 53 at its lefthandarmature and back contact breaks the circuit for relay'50 which isnormally bridged across the tip and ring leads of toll line 4. Thislatter relay which may or may not be operated depending on the presenceor absence of ringing current on the toll line, will by therelease ofits armature open the original energizing circuit for relay 52 which inreleasing opens the original `energizing circuit for relay 54, so thatrelay 53 by operating and in opening the 'locking circuit for relay 54at its make-before-b-reak contacts now permits relay 54 to release andextinguish signal 59. It should be noted, however, that the operation ofrelay 53 provides obvious substitute circuits for maintaining busysignals 57 and 58 and relay 55 operated. It is also clear that thebattery supplied at the sleeve of ack .3 will now furnish a busypotential for the sleeves of jacks 15 and y19. lThe busy conditionsestablished at the through, outward and A operators positions aretherefore maintained and controlled by relay 53 until plug.2 is removedlfrom jack 3 at the end of the conversation when it releases and returnsthe toll line circuit to normal.

' ln case the incoming call on this toll line is intended for a throughconnection, thel inward operator receiving this information transfersthe call to the through operators position at .13 by operating key 62.The operation of key 62 operates relays 54 and 60 over a circuit asfollows: battery, right-hand winding of relay 54,`righthand armature andback contact of'r'elay 63, left-hand winding of relay to ground at key62. The operation of relay 60 breaks the energizing circuit for relay 53from the sleeve of jack 3, restoring this relay. to normal, while relay54 in operating maintains at its right-hand armature and front contactthe circuit for busy signals 57 and 58and through the maintenance ofrelay 55 energized by this same circuit the busy signal 7 0 is alsomaintained operated in a manner that is considered obvious in view ofthe previous description. lt should be noted that lamp 6.4 associatedwith the through operators position 13 will now be lighted over acircuit from' battery at the make-before-break Contact of relay 53,leftl hand armature and front contact of relay 54, right-hand armatureand front contact of relay 60, right-hand winding of relay lul) lll]

lll

60 through lamp 64 to ground while lamp 59 is extinguished by theoperator of the right-hand armature of relay 60. Relay 60 is nowmaintained operated through the circuit from battery at relay 53. Theoperator at the throughy position 13 now insertsher plug 1A in jack 15and extends the call through to the distant exchange, as hereinbeforestated, over a toll line such as 18. The insertion of plug 1l in j ack15 now operates relay 53 causing` relays 54e and 60 to be released andsignal 64 to be extinguished. It should be noted that should the inwardoperator neglect to release key 62 signal 64 is neverthelessextinguished even though relays 54- and 60 may thereby remain operated.

Should the operator find that the incoming call requires the attentionof the outward voperator at 20 she manipulates key 65 and operationssimilar to those described for a through connection take place exceptthat relay 61 is operated in place of relay 60 and the. outwardoperators lamp 66 is lighted in place of lamp 64. In attending tooutgoing calls over the toll line 4t, under these circumstances theoperator at 20 may,vby inserting` plug 35 in jack 19, close a connectionfor the tip and ring leads over the toll line as is the usual practiceand also establish a sleeve circuit as follows: battery on the sleevecontact of plug 35 of a cord circuit similar to that shown at the rightof jack 19, sleeve contact of this jack 19winding of relay 53 to ground.The operation of relay 53 causes the release of relays 5ft and61 butbusy signals 57, 58 and 70 are maintained as hereinbefore describedoperated from' battery at the front contact of relay and lamp 66 isextinguished.

In cases where the outward operator originates an outgoing call, thatis, without the intervention of the inward operator the procedure is thesame except that the insertion of plug 35 in jack 19 will merely operaterelay 53 and thereby cause the operation of busy signals 57 and 58directly and busy signal indirectly by the operation of relay 55 andalso establish a busy potential on the sleeve of jacks 3, 15 and 40 ashereinbefore described.

If an outgoing toll call can be attended to by the A operator withoutthe aid of intermediate `operators by extending the connection directlyfrom her position through a multiple jack l0 she inserts plug 29 in thisjack and a connection is then established as follows: first, sleevecircuit may be traced from battery, lamp 79, sleeve contacts of plug 29and jack 40, lower armature and ack contact of relay 55, winding ofrelay 63 to ground. rllhe operation of relay 63 closes a circuit forrelay 72 and another circuit for relay 56 from battery through therespective windings of these relays to ground through `the left handarmaturel and front Contact of relay 63. The operation of relay 72disconnects the tip and ring leads of the inward, through and outwardjacks 3, 15 and 19, respectively, which are normally associated with thetoll line 4- and completes the talking leads fromthe j ack 40 at the Aoperators position to this outgoing end. Relay 72 also closes at itsouter lower armature a series connection for the all busy circuithereinbefore mentioned. The operation of relay 56 closes an obviouscircuit for the busy signal 70 at its lower armature and front contactand at its upper outer armature and front contact closes an operatingcircuit for relay 53 and at the same time provides a busy potential atthe sleeves of the inward, through and outward jacks. Relay 56 alsoopens a circuit 'for relay 55 so thatV when relay 53 operates this relaycannot become energized which is obviously not necessary in this type ofconnection. TheV operation of relay 53 closes a circuit for the busysignals 57' and 58 as hereinbefore described and opens at its left handarmature and back contact the circuit for relay 50.y This is to preventthe operation of relays 50, 52 and 54;

in this type of connection when ringing cury rent is applied which maybe done by the operation of the usual ringing key 8O in thel A operatorscord circuit.

rThe inductance in parallel with jack 40 is provided to put a` shuntacross the tip and ring of the A operators cord to extinguishsupervisory lamp 7 9 so that the operator will not inadvertently takedown the connection during a conversation. In Fig. 2 an inductance of asimilar nature is closed across the tip and ring of jack 10 through thecontacts of a relay, whereby a more elaborate supervision is provided,as will be explained hereinafter.

ln the modified form of the toll line shown in Fig. 2, the resultsobtained will be the same as with the circuit shown in Fig. 1 anddescribed above. It is identical with the preferred form of theinvention, only such changes being made as are necessary for theinclusion of the special supervisory features mentioned above.` As faras practical, the same referenceV numerals have been applied tocorresponding parts in the two circuits.

Incoming calls rreceived over this circuit causes relays 50 and 54 tooperate in succession. Relay 54 being locked up from the battery at themake-before-break contact of relay 53 causes the lighting of lamp 59.The busy signals 57, 58 and 70 are operated through circuits establishedat the inner left armature and front contact of relay 54 which alsoestablishesa busy potential on the sleeve of multiple jack 40. Vhen theinward operator answers this call, relay 53 operates and causes the samefuI1ctions to take place as in the preferred form when relay 53operates. Through and outward callsat jacks l5 and 19 also affect thecircuit ,in the same manner as described in connection with F ig. l andas the circuits in relation to these operations are easily traced, nofurther description will be made in this respect.

In 4extending toll connections directly from the A operators position,the operation of the circuits is also similar to that `described in Fig.1that is, relay 63 operates when plug 29 is inserted in jack 40y and theoperation of this relay causes the operation of relays and 72. Relay 72as stated, extends the tip and ring from jack to the toll line 4 andrelay 56 establislies the desired busy conditions. Relay 56 alsocompletes a portion of a circuit for transmitted to the other end of thetoll line- 4 where it will operate relay 50 which thereupon closes anobvious circuit for relay 7 6 through the inner lower armature and frontcontact of relay 56. Upon `the operation of relay 76 a shunt across thetip and ring of the A operators cord is opened sov that the supervisorylamp 7 9 becomes illuminat- Thus one A operator may signal' another. Assoon as lrey 8O is released relays and 76 are released and the bridgeacross the tip and ring of the cord circuit is closed causing theoperation of relay 78 to extinguish lamp 79 asis well known in the art.

If the operator at the distant end decides to call the A operator forthe further supervision of the established connection,

y ringing current is supplied to the toll line 4 from thel distant endas is Well known in the art, causing the operation of relay 50. As theringing key of the operators cord circuit is now released, the operationof relay 50 and the consequent operation of relay 76 and opening of thebridge acrossthe tip and ring of the local jack, causes the release ofrelay v78 and the lighting-of lamp 79. Condensers 82 and 83 are insertedin the tip and ring leads and the'circuit in order that relay 50 mayoperate on the incoming ringing current.

Condenser 84 is inserted in series with rebattery and ground'suppliedfrom the A operators coi'd when plug 29 is connected to jack 40. i Whatis claimed is:

l. In' a telephone system, a transmission line terminating in two groupsof jacks each f at. a plurality of positions in a central office, onegroup normally connected and the other normally disconnected from saidline, means vresponsive to a connection established through the jacks ofeither group fory rendering attempted.. connections through the jacks ofthe other group ineffective, a busy signal at several of said positions,a Acall signal at one of saidpositions and a ringing responsive meansfor operating thecalll signal, for operating the busy signals and forestablishing a busy condition on the sleeve of the jack at certain ofsaid positions, means for maintaining said call signal and busy signaloperated and the established busy condition effective after thecessation of the ringing, and means responsive to the answering of thecall at the position where the call signal is located for releasing saidcall signal, for maintaining the busy signal operated, for maintainingthe established busy conditions effective and for establishing abusycondition on the sleeve of the jacks at the remaining positions.

2. In a telephone system, a transmission line terminating in two groupsof acks each at a plurality of positions in a central` oftice, one groupnormally connected and the other normally disconnected from said line,means responsive to a connection established through the jacks of eithergroup for renderingk attempted connections through the jacks of theother group ineffective, a busy signal at certain of said positions, acall signal at certain of said positions, a ringing responsive means foroperating the call signal at one of the positions, for operating all ofsaid busy signals and for establishing a busy condition on the sleevesof the jacks at certain of said positions, means for maintaining saidcall signal and the busy signals operated and the established busyconditions effective after ringing has ceased, means for releasing theoperated call signal and operating any oneof the other call signals,means responsive in answering the call at the position where theassociated call signal is operated for releasing said call signal,fortransferring the control over the busy signals and the establishedbusy conditions to said last mentioned means, for maintaining said busysignals operated and the busy conditions effective and for establishingbusy conditions on the sleeve of the l jacks at the remaining positions.

3. In a telephone system, a transmission line terminating in two groupsof jacks each at a plurality of positions in a central of- 1 lice, onegroup normally connected and the other normally disconnected `from saidline, means for calling from any of the acks normally connected to theItransmission line, rmeans for calling' Afrom any of the normallyrdisconnected jacks operative to connect said jacks to the line anddisconnect the jacks of the kother group from lthe line, and meansresponsive to a call from any jack for es- ;tablishing busy indicationsat all of said positions. p

4. In a telephone system, a transmission line terminating in two groupsof jacks each :at a `plurality of positions ina central ofice, busysignals at all of the jacks of one group' and at all but oneof the jacksof the other group, means for operating said busy ,signals and forestablishing' a busy condition at the jack at which no busy signal islocated operative When a connection is ,made througha Jack of eithergroup, and means i'or disabling the jacks of one group VWhen connectionis made through a jack of the Y ERNEST L. BAULCH.

